MHEV Battery Charging

The MHEV  battery is charged by the BISG  with energy from the following sources:

• Recovered energy when the engine overruns.
  • This uses energy derived from deceleration when the accelerator is released. The crankshaft is being driven by the transmission as the vehicle slows down. The BISG  recovers the energy that would otherwise be lost and fully charges the MHEV  battery.
• Engine torque
  • On extended motorway journeys there may be limited opportunities to recover energy during deceleration. In these circumstances energy is taken from the engine when the vehicle is cruising to maintain a minimal battery State of Charge.

The PCM  monitors the MHEV  battery State of Charge. The PCM  determines when is the most efficient time to charge the MHEV  battery. The PCM  only charges the MHEV  battery to a specific State of Charge with engine torque. The MHEV  battery can be charged to the maximum State of Charge with the recovered energy when the engine overruns. The recovered energy can then be used by the BISG  to provide engine assist when required.